(CNN) - Despite swearing off public life earlier this year, peace activist Cindy Sheehan would run against House Speaker Nancy Pelosi as an independent in 2008 unless the speaker moves to impeach President Bush, a Sheehan spokeswoman said Sunday.

Sheehan, a northern California resident, is taking part in a protest caravan from President Bush's home in Crawford, Texas, to Washington, which is scheduled to arrive July 23. Spokeswoman Tiffany Burns told CNN that Sheehan would challenge the speaker, who has held her San Francisco-area seat since 1987, unless Pelosi introduces articles of impeachment before then.

There was no immediate reaction from Pelosi's office to Sheehan's threat. The speaker said in November that calls for impeaching Bush were "off the table," but that Congress would push for an end to the widely unpopular, 4-year-old war under Democratic control.

Sheehan achieved national attention when she camped outside Bush's home throughout August 2005 to demand a meeting with the president over her son's death. While Bush ignored her, the vigil made her one of the most prominent figures among opponents of the war.

But in May, after congressional Democratic efforts to set a March 2008 goal for a U.S. withdrawal from Iraq failed in the face of a presidential veto, Sheehan quit the anti-war movement in disgust and declared that her son Casey - a U.S. soldier killed in Baghdad in 2004 - had died "for nothing."

She said she was exhausted by the personal, financial and emotional toll her campaign had taken, disillusioned by the failure of Democratic politicians to end the war and tired of a peace movement she said "often puts personal egos above peace and human life."

I believe we need to remove all of our present government and install a completely new government as OUR CONSTITUTION says WE THE PEOPLE can do if our present form of government fails to perform as WE THE PEOPLE direct it to do. BUT I THINK THE AMERICAN PEOPLE WANT PEOPLE IN THEIR NEWLY FORMED GOVERNMENT LIKE THE PEOPLE WHO FIRST FORMED IT IN THE BEGINNING, NOT SOME RADICALS WHO ARE PUSHING A "CAUSE" AND WHO HAVE LITTLE EXPERIENCE IN GOVERNMENTAL AFFAIRS AND THE MORAL STANDING AND COMPREHENSION OF WHAT MAKES AMERICA GREAT. YES, NANCY PELOSI NEEDS TO BE KICKED OUT OF OFFICE BUT SO DOES THE REST OF THE GOVERNMENT.

I personally don't care if she runs or not. What difference will it make? None at all... If she runs, nothing will change. If she loses, nothing will change. If she wins, nothing will change. If she doesn't run, nothing will change. The government will still do what they want to do, and there is nothing that you, or I, or anyone can do about it.

Those who vilify Cindy are the same fools that are willing to sit back and let the Bush Gestapo continue to run rampant over the Constitution and the Rule of Law. She is woman who is willing to fight for her beliefs unlike the majority of those on Capitol Hill. If her actions causes Bush and Chaney to be accountable for their crimes against this country and the world millions will support her. Polls show that the majority of our citizens are in favor of impeachment so her courageous actions might be the catalyst to move this important issue forward.

Pelosi's "Impeachment is off the table" comment is a real kick in the teeth to anyone who either has integrity, or wants to live in a lawful democracy. Think of the loooong list of laws broken by the Bush administration, including the bloody & illegal occupation of Iraq. Impeachment should have been the FIRST item on the agenda. If Sheehan wants to join the ranks & try to fix this very broken government system, go for it. At least someone in government would have a spine.

What about 911 you poeple do not understand. The Germans, French, and Brits along with THE UN said Iraq had WMDs. Democratic politicians voted to go to war also and are now lieing as to why they did, and 53% of the people voted for Bush in 2004 5% more the voted for Clinton. OH by the way Sheehans son ask to be in the Army and none of those young poeple serving were forced to serve, UNLIKE most of those who went to Vetnam. Also each and every terrorist going to Iraq is on less comming to the U.S. Bush has made some erroes ans so will any leader, but remenber no attacks for 6 years on U.S. soil, Good Record!!!

I admire her courage, even if she doesn't stand a chance. The Bush administration should be held accountable for the many disasters they've caused our country. Are you listening, Nancy? The Democrats need some guts and stop being so pathetic. Newt Gingrich would've had Clinton impeached and imprisoned for treason if he were in Bush's shoes (which he wouldn't be) today and the same Republican congress of the 90s was in charge. And this is a thousand times worse than a freakin' sexual lie!

"upholding the US Constitution?" You cannot impeach a president for doing his job. Article 2 the Constitution states: "The President shall be Commander in Chief of the Army and Navy of the United States, and of the Militia of the several States..." I believe the war is wrong, but impeachment for using his Constitutional powers? I don't care what kind of president we have; we as a country must protect the Constitution not use it for our own emotional well being.

I am sorry she lost a child. I know it's difficult to endure. I also respect her right to not like the current administration. But she's turned her "cause" into a personal vendetta & I do not feel she is qualified or capable of being in office. She could not put her emotional feelings aside to do what would need to be done. She would not serve the best interest of the American people.

Good idea Cindy: pressure Nancy Pelosi. Maybe then she will remember why she got elected by progressives in the first place, and maybe Georges "president-run-amok" Bush will finally get what he deserves: an impeachment.

Cindy's 15 minutes af fame were over along time ago. She has turned into a sad emotional train wreck. She should take a page from her now ex-husband and realize that her son died for each and everyone of us preserving our freedom. How sad that her son has been lost in all of her rantings. She claims that this is all for Casey, but she never talked about him so none of us even know who he is. How sad for his memory. I am so thankful for our solders and beleive that they are doing a wonderful job with what they are given. It's a tough assignment and they do it with pride and dignity! Wake up Cindy and show some respect for your Casey and the service he provided. Thank you Casey!

I'm so tired of seeing Sheehan's name in the news. She's nothing but a bitter old woman pretending she cares about the rest of this country. Pelosi isn't any better. I wish someone with brains would get in there. I'm a woman and neither of them represent me at all. who does Cindy Sheehan think she is by giving an ultimatum anyway? I'm an independant with beliefs that go in each party, but I'd have to say I see the Democratic party sinking lower and lower every day because of people like these. They make me sick to know some fool would actually vote for them.

I am sorry for the loss of Miss Sheehan's son in Iraq. But her son joined the military knowing what could happen to him. He is a hero and a great American just as the other Americans who have died in Iraq. Stop it Miss Sheehan. The President did not kill your son!

Sure. Let her run. But we all know that the powers that be will not allow her to speakns yet let alone win..she has no big money backing her up. This is America...home of the money....many of the poor...and the mass media will see to it that common citizens like Sheehan and tell the truth presidential candidates like Ron Paul will never allow their voice to be heard...Its time for a change...

For God's sake Sheehan, don't go up against another woman. Do your thing with the Dems but do it with them. We're with you. Let's not further fracture what is already frail and broken. Bind together what is drifting. We stopped them before; we'll stop them again.
Kiki in Lake Geneva

Cindy, when your son signed up to join the military, it was an honorable and brave thing to do. He knew the chances he was taking. When you join the US military, you go to war when you are given the order. You do not question the order. You obey it. Your son did just that. He is a hero. I do not think that your son would be very proud of you right now. The war is over for you Cindy. Give it a rest.

I feel bad for her. She thinks the Democrats can end the war, because thats what they were elected to do. Well guess what...thats not how it works. You need 67 votes to override a veto Cindy. Also she wants Bush impeached. He may be a terrible president, but there is no proof that he did anything illeagal...yet. Pelosi gets re-elected with like 90 percent of the vote, so good luck with that campaign Cindy.